1. Field of the Invention
The present invention relates to an image processing apparatus, image processing method, and storage medium, which are required to apply recognition processing to an image sensed by an image sensing device which can sense a broad-range image.
2. Description of the Related Art
A method of sensing a broad-range image at once compared to an image sensing device having a normal field angle using a broad-range image sensing device such as a fish-eye lens or omni-directional mirror is known. Japanese Patent Laid-Open Nos. 2008-048443 and 2002-064812 disclose a technique for detecting a moving object from an image sensed by such broad-range image sensing device, and automatically deciding and tracing that moving object extraction region. In these patent literatures, distortions are removed from the moving object by correcting the distortions caused by the image sensing device.
When the omni-directional mirror is used as the broad-range image sensing device, panoramic extension and perspective projection extension are popularly used as an image distortion correction method. The panoramic extension is a method which assumes a virtual column around the omni-directional mirror, and projects a broad-range image onto the side surface of the column. The perspective projection extension is a method which assumes a vertical plane from a focal point of the omni-directional mirror in a certain visual axis direction, and projects a broad-range image onto the vertical plane. Also, Japanese Patent Laid-Open No. 2008-165792 discloses a technique for moving object detection. Furthermore, Japanese Patent Laid-Open Nos. 2009-211311 and 2008-234169 disclose a technique for object recognition such as human body detection and face detection.
There are needs for applying object recognition processing such as human body detection, face detection, or face recognition to an image (broad-range image) sensed by a broad-range image sensing device. An existing object recognition method is designed to be applied to an image sensed by an image sensing device having a normal field angle. For this reason, in order to apply such object recognition to a broad-range image, processing for correcting image distortions caused by the broad-range image sensing device has to be executed as pre-processing.
On the other hand, a resolution of image sensors used in the broad-range image sensing device is increasingly enhanced. For this reason, when the aforementioned pre-processing is applied to an image sensed by such broad-range image sensing device, a processing volume required for this pre-processing increases compared to the conventional device, and real-time object recognition cannot be done at a high frame rate.